A brushless direct current (BLDC) motor may prevent friction and wear which are disadvantages of the existing DC motor and have relatively high efficiency. Therefore, recently, hybrid cars tend to adopt the BLDC motor as a motor for rotating a cooling fan.
The BLDC motor is a motor that does not have a brush and a commutator necessary for a DC motor but has an electronic commutation mechanism installed therein.
Further, the existing BLDC motor assembly has a motor unit and an inverter unit that are formed integrally, and thus is configured of an inverter built-in BLDC motor. Here, as illustrated in FIG. 1, an inverter unit 20 is coupled to one side of a motor unit 10. Meanwhile, the inverter unit 20 is formed to include a PCB substrate provided in an internal space formed by an inverter housing 21 and a cover 22 that are coupled to each other.
Here, a motor head part 12 extends to be provided in the inverter housing 21 and is provided with a bearing 13 rotatably coupled to a rotating shaft 11 of a rotor 16 provided in the motor unit 10. At this time, a sealing member such as an O-ring is assembled for sealing between the bearing disposed on the left side of FIG. 1 and the motor head part in the drawing, an O-ring cover is assembled to fix the O-ring, and a stop ring (snap ring) or the like is used to prevent the O-ring cover from being separated from the inverter housing.
As a result, there is a problem in that the sealing member is pressed to be damaged during the assembly, and therefore moisture may be infiltrated into the inverter unit and a plurality of parts are used, and therefore assembling performance is lowered and manufacturing cost is increased. Further, the inverter housing is provided with a groove into which the bearing is inserted. By the groove, an inner bottom surface of the inverter housing is concavely formed without being flattened. Therefore, it is difficult to radiate heat because heat is transferred through the groove portion, and it is difficult to design a PCB substrate because a switching device having a large amount of heat generation may not be disposed at a position opposite to the groove portion on the PCB substrate provided in the inverter unit.